Methylacetylene diadducts of dialkyl dithiophosphoric acids

ABSTRACT

METHYLACETYLENE DIADDUCTS OF DIALKYL DITHIOPHOSPHORIC ACIDS ARE PREPARED BIA SELECTIVE FREE RADICAL AND ELECTROPHILIC REACTIONS. THE FREE RADICALS REACTIONS CAN BE CARRIED OUT TO YIELD THE CORRESPONDING VINYLIC DITHIOPHOSPHATE MONOADDUCTS. THESE IN TURN ARE REACTED WITH THIOLS TO YIELD SEQUENTIAL DIADDUCTS. SOME OF THE NOVEL SEQUENTIAL DIADDUCT DITHIOPHOSPHATE ESTERS ARE UNEXPECTEDLY SUITABLE FOR ANIMAL INSECTICIDE APPLICATIONS, DUE TO THE DETOXIFYING EFFECT OF THEIR B-ALKYL SUBSTITUTENTS ON THE HYDROCARBYLTHIOETHYL MOIETY.

United States Patent Oflice 3,733,377 Patented May 15, 1973 3,733,377METHYLACETYLENE DIADDUCTS OF DIALKYL DITHIOPHOSPHORIC ACIDS Alexis A.Oswald, Mountainside, N.J., assignor to Esso Research and EngineeringCompany No Drawing. Continuation-impart of abandoned application Ser.No. 518,028, Jan. 3, 1966. This application Mar. 15, 1971, Ser. No.124,564

Int. Cl. Aln 9/36; C071 9/16; C10m 1/48 US. Cl. 260-948 5 ClaimsABSTRACT OF THE DISCLOSURE Methylacetylene diadducts of dialkyldithiophosphoric acids are prepared via selective free radical andelectrophilic reactions. The free radical reactions can be carried outto yield the corresponding vinylic dithiophosphate monoadducts. These inturn are reacted with thiols to yield sequential diadducts. Some of thenovel sequential diadduct dithiophosphate esters are unexpectedlysuitable for animal insecticide applications, due to the detoxifyingeffect of their p-alkyl substituents on the hydrocarbylthioethyl moiety.

CROSS-REFERENCE TO OTHER APPLICATIONS This application is acontinuation-in-part of an application, entitled Adducts of DialkylDithiophosphoric Acid, of Ser. No. 518,028 which was filed on Jan. 3,1966 and which is now abandoned.

FIELD OF THE INVENTION This invention relates to novel organophosphoruscompounds and to novel processes for preparing the same. In particular,this invention relates to methylacetylene diadducts of dialkyldithiophosphoric acids. Of special interest are the radical typediadducts, which are prepared by a mono-addition of a dialkyldithiophosphoric acid followed by the addition of an organic thiol. Someof these adducts, i.e. j3-methyl substituted S-hydrocarbylthioethyllower dialkyl dithiophosphates are unexpectedly safe and elfectivepesticides.

PRIOR ART VERSUS PRESENT INVENTION The reaction between0,0'-dihydrocarbyl dithiophosphoric acids and a variety of unsaturatedorganic compounds is known to produce monoand diadducts of theunsaturate. For referense, see Houben-Weyl, Methoden der OrganischenChemie, vol. XII/2, Organische Phosphor-Verbindungen, pp. 709-720, ed.,E. Mueller, pubL, G. Thieme Verlag, Stuttgart, Geermany, 1964, and U.S.Pats. 3,340,332 and 3,449,474. Some of these adducts possess propertieswhich makes them suitable as lubricating oil additives and/0rpesticides. The importance of selected members of the known types ofadducts has stimulated interest in other adducts and in novel selectivemethods of their preparation.

The mono-addition of dialkyl dithiophosphoric acids to equimolar amountsof acetylene and alkylacetylenes in the presence of chemical freeradical initiators is described in the prior art. See, for example, US.Pat. 3,067,- 232. It is also described in the same patent, thatactivated acetylenes such as phenylacetylene and dimethylacetylenedicarboxylate can be reacted with dialkyl dithiophosphoric acids at lowtemperatures. Nonactivated acetylenes, such as acetylene itself andalkylacetylenes, particularly methylacetylene, were known to react onlyat higher temperatures, where side reactions occur.

In the present invention, a selective low temperature process was foundfor the preparation of novel free radical monoadducts ofmethylacetylene. Besides the use of low temperatures, anotherdistinguishing feature of the present free radical process is the use ofnonchemical type, i.e., radiation, reaction initiators. Both of thesefeatures are important not only in making novel free radicalmethylacetylene monoadducts available, but in making the novel additionprocess safer than the known nonselective high temperature processes.

Surprisingly, it was also found in the present invention that dialkyldithiophosphoric acids readily react with alkylacetylenes by a cationicmechanism in the absence of added catalysts to yield the correspondingMarkovnikov type monoand diadducts.

The diaddition of dialkyl dithiophosphoric acids to acetylenes is notdescribed in the prior art. A copending application of ours, i.e. Ser.No. 884,046 filed on Dec. 10, 1969, now abandoned, describes that twomoles of a dialkyl monothiophosphoric acid could not be added to onemole of methylacetylene. In view of this, it is especially surprisingthat it was found in the present invention that the diaddition ofdialkyl dithiophosphoric acids to methylacetylene does take place viaboth free radical and cationic mechanisms.

SUMMARY OF THE INVENTION In the present invention, it has beensurprisingly found that, in the presence of nonchemical free radicalinitiators, alkylacetylenes, such as methylacetylene, and dialkyldithiophosphoric acids react in a free radical manner at lowtemperatures. To distinguish the present invention over the prior art,the novel process was compared with known higher temperature processesfor the reaction of alkylacetylenes with dialkyl dithiophosphoric acids.It was found that a higher temperature process, of reactingmethylacetylene and a dialkyl dithiophosphoric acid as disclosed in US.Pat. 3,067,232, leads, already at 50 C., to diadduct formation by thefollowing reactions:

It was furthermore observed that the monoadduct precursor, i.e.,S-isopropenyl dialkyldithiophosphate (I) of this diadduct,2,2-bis-dialkylthiophosphorylmercapto-prm pane (II), could not beisolated when equimolar amounts of reactants were used. It is assumedthat under these experimental conditions, this adduct (I) is extremelyreactive towards another mole of dialkyldithiophosphoric acid.

The structure of the final product shows that cationic additions tookplace instead of the expected free radical additions. Such additions areelfectively catalyzed by the dialkyl dithiophosphoric acid reactant atthe higher reaction temperatures of the prior art and as such will occurboth in the presence and in the absence of free radical initiators.

However, in accordance with one aspect of the present invention, it wasfound that the desirable free radical additions can be carried out withalkyl acetylenes if different process conditions are used. At first, itwas observed that the ionic additions could be suppressed if highlyelevated temperatures are avoided. Free radical reactions, on the otherhand, could be initiated at ambient temperatures or below by nonchemicalmeans, i.e., by ultraviolet or gamma irradiation. Dependent on therelative molar ratio of reactants these reactions were found to yieldeither the radical monoadducts, e.g., S-propenyl-dialkyldithiophosphate(III) or the radical diadduct, e.g.,ois-l.2-dialkylthiophosphorylmercapto-propane (IV) as the main products.These reactions in the case of methylacetylene can be depicted asfollows:

(3) 01150 hPSzII .ROMSCHLQH l ll CH3 3' CH3 lIIl) (R);P s CII=CII(ROhlSzll .RUhPSCIIzCU s W lli);

CH3 CH3 LIV) According to another aspect of the present invention. ithas been found that the radical monoadducts can be further reacted withan organic thiol to yield mixed radical diadducts. For example, themethylacetylene monoadducts, i.e., S-propenyl dihydrocarbyldithiophosphates (III) can be reacted with thiols as indicated by thet'ol lowing Equation 5.

g (1H3 b CH3 (III) N In the preparation of these mixed adducts LV).i.e.. reaction 5, radiation and conventional chemical free radicalinitiators can both be used. The order of these mixed diadditions is,however, extremely important oecause alkenyl hydrocarbyl sulfides reactspontaneously with dialkyldithiophosphoric acids in an ionic manner toyield mixed diadducts of a different type. .-\n example of this type ofreaction is depicted hereinbelow reaction 6) to yieldS-l-hydrocarbylmercaptopropyl dialkyldithiophosphates (VI).

These mixed diadducts of the present invention ilype V) are particularlydesirable for pesticidal use. When compared to pesticidal phosphateesters of somewhat similar structure, they showed a relatively low levelof toxicity towards warm-blooded animals, such as mice, rats, guineapigs, cats and cows. i.e., a greater level of safety when used aspesticides. This safety allows the use of the present compounds in newfields of applications. e.g., as systemic animal insecticides.

As an example of the high toxicity of prior art compounds of similarstructure, the median lethal dose (LD for mice for the compound,

(CzIIsOhISCHzCIIzSCglIs is about 6 mg. per body kg. See the monographentitled Die Entwicklung neuer Insektizider Phosphorsaui'e- Ester, byGerhard Schrader published by Verlag Chemie GrnbH., Weinheim/Bergstr.,Germany in 1963. In contrast, the mixed diadducts depicted by Formula Vshow LD values in the range of 2S-250 mg. per kg. of body weight.Moreover, all of the diadducts of the present invention have a primaryphosphate ester structure. which is more resistant to hydrolysis thanthe secondary or tertiary ester structures. From a practical viewpoint,this resistance is very important because these compounds are often usedin the form of an aqueous emulsion for pesticidal spray applications.

It is therefore, an object of the present invention to provide the artwith novel dihydrocarbyl dithiophosphoric acid and adducts ofacetylenes. Another object of the present invention is to provide aprocess for preparing such novel adducts. This invention also describesan improved. safer method or controlling pests with the novelcompositions. In this respect. this application describes .1 novel.unexpected use as systemic animal insecticides. Finally, the srproperiyldihydrocarbyl dithiophosphate adducts of the present invention are alsouseful as lubricathg additives.

The exact nature or the present invention will be more :learly perceivedand fully understood by referring to be following description andclaims.

rocess reactants The S-propenyi .1ihydi-ocarbyldithiophosphateinternediates or :he present invention are prepared by reactng methylacetylene Nllh a .iihydrocarbylidithiophospnoric acid having mefollowing structural formula:

f-Sll .,,o

Wl'16l'6ll'l R and R represent any hydrocarbon radical, inch as forexample. alkyl, aryl or substituted aryl. Particularly preterredcompounds of this invention are preaared from acids wherein R and R areeach selected from the group consisting of C C alkyl, C -C aryl, C -Caikaryl or araikyl. and halo and nitro substituted tI -C aryl. Forpesticidal applications, especially prel'erred compounds are preparedfrom acids wherein R and R are each selected from the group consistingof C -C alkyl and C -C aryl.

Suitable examples or R and R include: (a) methyl, ethyl, n-propyl.i-propyl. outyl, pentyl, octyl, decyl, pentadecyl. octadecyl. dodecyl.eicosyl, docosyl, pentacosyl and :riacontyl: lb) phenyl, ethylphenyl,toluyl, \ZVlyl. and napnthyl; ic) Z-chlorophenyl, 3-bromo-phenyl,i-cnloro-toluvl. dichloro-toluyl; and (d) Z-nitro-phenyl,T-nitro-toluyl. l-nitro-m-xylyl. and 1.5-dinitro-m-xylyl.

The preferred reaction product derived from these reictants .tndmethylacetylene has the general formula:

ivherein the meaning or the various R groups is the same.

The S-Z hydrocarbylmercaptopropyl dihydrocarbyldithiophospnate productsor the present invention are prepared b reacting the above S-propenyldihydrocarbyltlithiophospnate intermediates with hydrocarbon thiols Jfthe formula:

i -SH wherein R4 is selected from the group consisting of C -C .likyl.C( C JLIVl. C -C .Ilkaryl. halo-substituted C C aryl. .indnitro-substituted C C aryl. Preferably, R is a C.-C, alkyl group.

Suitable examples or organic thiols include: methanerhiol, ethanethiol.n-propanethiol, 'i-propanethiol, n-bu- :anethiol. benzenethiol,@t-napnthalenethiol. o-toluenethiol. -chlorobenzenethiol. 4 nitrobenzenethiol, 3-chlorop-toluenethiol. 3.4 dichlorobenzenethiol, and4-methyl- :nercaptobenzenethiol. 4-fluorobenzenethiol.

'rocess conditions The free radical type reaction betweenmethylacetylene and the dihydrocarbyldithiophosphoric acid can becarried out at a temperature or between about 80 C. and about 40 C..preferably between about 0 C. and about 30 C.. more preferably, atambient temperatures, i.e. between about 16 C. and about 28 C. Thereaction can be performed in the liquid phase at pressures of betweenabout atmospheric and about atmospheres. However, tutogeneous pressuresresulting from methyl acetylene are preferred.

The catalysts employed in the above-described reaction are nonchemicalfree radical initiators. Suitable, nonchemical free radical initiatorsinclude ultraviolet light and gamma radiation. Ultraviolet light ispreferred. In general, the source of the ultraviolet light or gamma(X)-ray radiation is not critical. A 70-wat-t high pressure mercury arclamp which emits a light of wide spectrum wavelength can be suitablyemployed in the laboratory; however, any source of ultraviolet lightregardless of the quantity of wattage can be used. It should be notedthat the more intense the source, the faster the reaction proceeds. Inthe case of gamma radiation, a thousand to ten thousand Curie (C sourceis, for example, suitable to initiate the reaction from a distance ofabout 6 cm.

The general preference for initiation by radiation is due to the higherselectivity of the reaction at lower reaction temperatures. Theinitiation by radiation can be readily accomplished at low temperatures,while most chemical initiators must be used at elevated temperatures.

In preparing the monoadduct of methylacetylene and thedihydrocarbyldithiophosphoric acid, mole ratios of methylacetylene tothe dihydrocarbyldithiophosphoric acid can range between about 1:1 andabout :1. The preferred reactant ratios are between 2:1 and 4: 1. Whenthe principal product desired is the diadduct, the mole ratio of methylacetylene to the dihydrocarbyldithiophosphoric acid ranges between about1:3 and about 2:1, preferably between 1:3 and 1:2.

The nonchemical free radical initiated reaction between methylacetyleneand a dihydrocarbyldithiophosphoric acid can be carried out in thepresence of an inert diluent. Preferably, no diluent is employed.Suitable diluents which can be employed, if desired, include: C -Caliphatic hydrocarbons, such as octane, C -C cycloaliphatichydrocarbons, such as cyclohexane, ethers, such as diethyl ether, andthioethers, such as dimethyl sulfide.

The free radical type reaction between the unsaturated monoadduct ofmethylacetylene, i.e., the S-propenyl dihydrocarbyldithiophosphate,VIII, and the organic thiol, IX, can be carried out at a temperature ofbetween about 80 C. and about 100 C. If radiation is used for reactioninitiation, the temperature should be preferably between about 80 C. andabout 40. C., more preferably between about 0 C. and about 30 C., andmore preferably at ambient temperature, i.e., between about 16 C. andabout 28 C. The preferred temperature range in the case of chemicalinitiators depends on the decomposition temperature of the initiatorcompound to be used. Pressures employed are, in general, atmospheric orautogenous, the latter of which can vary up to about atmospheres.

The preparation of the mixed diadduct is catalyzed by any conventionalfree radical initiator, both chemical and nonchemical. Specifically,such catalysts include ultraviolet light, gamma irradiation and a widevariety of organic peroxides, hydroperoxides and azo-compoundsconventionally employed as free radical initiators. Typical chemicalfree radical initiators include: cumene hydroperoxide, t-butylhydroperoxide, bis-t-butyl peroxide, benzoyl peroxide,azo-bis-isobutyronitrile, etc.

In general, the amount of chemical free radical initiator employed canvary over a broad range, but preferably it will range between about 0.05and about 5 mole percent based on the total amount of reactants.

The mole ratio of organic thiol compound to the S- propenyldihydrocarbyldithiophosphate can vary between about 1:1 and about 10:1,preferably between 1.0:1.1 and 1022.0. An excess of the organic thiolcompound is preferred when higher reaction rates and more completemonoadduct conversions are desired.

Suitable diluents can be employed to prepare the abovedescribed mixeddiadducts and those described in connection with the preparation of theS-propenyl dihydrocarbyldithiophosphates are suitable examples thereof.However, as in the case of the monoadduct preparation, it is preferrednot to use a diluent.

Compositions The novel compositions claimed in the present invention arerepresented by the general formula:

Ego CH3 wherein R and R are C to C unsubstituted hydrocarbon radicalsand C to C monosubstituted hydrocarbon radicals selected from saidmonochloro, mononitro substituted radicals. It is preferred that R and Rbe C to C saturated aliphatic, alkylphenyl and phenylalkyl hydrocarbonradicals and their monochloro and mononitroderivatives. More preferably,R and R are C to C alkyl radicals, phenyl, chlorophenyl, nitrophenyl, Cto C alkylphenyl, C to C phenylalkyl, C to C alkylchlorophenyl radicals.Most preferably, R and R are methyl and ethyl. The R, radical isselected from the group consisting of C to C alkyl, phenyl, 0 -0alkylphenyl, C -G phenylalkyl, chlorophenyl, bromophenyl, nitrophenyl.Preferably R is a C to C alkyl. Most preferably, R is methyl and ethyl.

The preferred compositions of the present invention are of the formula:

u Eu'H P-S CHiCH-S-R-l CnH2n+1O H3 wherein n is 1 and 10 and R is C to Calkyl, phenyl and chlorophenyl. These preferred compounds possess anespecially high degree of pesticidal activity.

The most preferred compositions of the present invention are of theformula:

ll n Zn-H S C 3 wherein m and n are 1 and 2.

Examples of suitable R R and R substituents were provided with thediscussion of the starting materials for these compositions.

Examples of the preferred novel compositions of the present inventionare listed in the following: dimethyl 2-ibutylthiopropyldithiophosphate, diethyl 2-p-chlorophenylthiopropyl dithiophosphate,methyl ethyl 2-i-propylthiopropyl dithiophosphate, ethyl cyclohexyl2-methylthiopropyl dithiophosphate, diphenyl ethylthiopropyldithiophosphate, ditolyl 2-trichlorophenylthiopropyl dithiophosphate,dipropyl 2-pentylthiopropyl dithiophosphate, ethyl propyl4-p-nitrophenyl dithiophosphate, ethyl benzyl 2-cyclopentylthiopropyldithiophosphate, dibutyl 2-p-tolylthiopropyl dithiophosphate.

The new diadducts are useful as pesticides. Some of them are outstandingsystemic pesticides relatively safe to use. Others are contactinsecticides. A few of them, due to their low toxicity, have a highpotential for controlling animal insects, preferably via systemicaction. Of course, dependent on their particular structure, they possessdifferent degrees of attractiveness for the various useful applications.Various concentrations of the different diadducts may be required asactive ingredients in pesticidal compositions to provide effectiveinsect control.

For example, the particularly attractive sequential diadducts from theviewpoint of systemic plant insecticide applications are those having asignificant degree of solubility in water. Water solubility allows suchcompounds to be transported in the plant sap from the roots to theleaves. In terms of substituents this means that from this viewpoint themost desirable diadducts have their R R and R groups selected frommethyl and ethyl groups.

From the viewpoint of contact insecticidal and fungicidal activity onthe other hand one may wish to select aromatic radical substituents,particularly for F The novel mixed diadducts of the present inventioncan be employed as pesticidal compositions in either a solid or liquidform. When used in a solid form. they may be reduced to an impalpablepowder and applied as an un diluted dust or mixed with a solid carriersuch as clay. talc and bentonite, as well as other inert carriersKI'IOWIT in the art. The mixed diadduct can also be applied as it sprayin a liquid carrier either as a solution in a solvent or in an emulsionin a non-solvent such as water. In the diluted solid or liquid form, themixed diadducts or the present invention can be employed in an amount otbetween about 0.0001 and about 15.0 wt. percent. based on the inertcarrier. Typical liquid solvents include such compounds as acetone,ethyl alcohol, benzene, naphtha, etc. Suitable wetting agents andemulsifying agents can also be employed in preparing the pesticidalcompositions. The mixed diadducts of the present process can also beadmixed with carriers that are themselves pesticides. Finally, theactive compounds of the present invention can be used without dilutionas an atomized mist.

EXAMPLE 1 A mixture of 94.8 grams (0.6 mole) of dimethyldithiophosphoricacid and 40 grams 1.0 mole) of methyl acetylene was irradiated at 17 C.with ultraviolet light from a high pressure mercury arc of 75 watt Hanauimmersion lamp for 24 hours with magnetic stirring in a closed quartztube. Subsequent distillation of the reaction mixture yielded 104.8grams (82%) of S-propenyl dimethyh dithiophosphate as a colorless liquidboiling between 60 64 C. at a pressure of 0.3 mm.

Analysis.--Calcd. for C H O PS (percent): C. 30.30: H, 5.59; P, 15.62;S, 32.35. Found (percent): C. 19.74: H, 5.50; P, 15.60; S, 32.21.

EXAMPLE 2 A mixture of 93 grams (0.5 mole) of diethyldithi'ophosphoricacid and 40 grams (1.0 mole) of methyl acetylene was reacted for 65hours under the conditions of Example 1. Subsequent distillation of thecrude product yielded 89.9 grams (79.5%) of S-propenyldiethyldithiophosphate as a yellow-tinted liquid boiling between 74-"8C. .it a pressure of 0.4 mm.

Anal vsi's.Calcd. for C H O PS (percent) C. 37.16: H, 6.68; P. 13.68: 5.28.34. Found (percent): C, 36.93: H, 6.55; 13.65; S 28.20.

EXAMPLE 3 A mixture of 47.4 grams (0.3 mole) of dimethyldithiophosphoricacid and 6 grams (0.15 mole) of methyl acetylene was reacted in themanner described in Example 1. The resulting colorless crude product wasfreed from the volatile S-propenyl dimethyldithiophosphate by-product byheating at 142 C. under 0.2 mm. pressure. This resulted in the recoveryof 7.20 grams of the monoadduct as a distillate boiling at 55-60 C. and36 grams (75%) of the 1.2 bis-dimethylthiophosphorylmercaptopropanediadduct as a slightly yellow, somewhat viscous. distillation residue.

Analysis.Calcd. for C I-1 0 155 (percent): C. 23.59; H, 5.09; P, 17.38;5, 35.99. Found (percent): C. 24.01; H, 5.02; P, 16.92; S, 36.10.

EXAMPLE 4 A mixture of 55.8 grams (0.3 mole) of diethyldithiophosphoricacid and 6 grams (0.15 mole) of methyl acet ylene was reacted in themanner described in Example 1. After the unreacted methyl acetylene wasallowed to escape, the resulting yellow crude product was heated to 150C. in vacuo to distill off the by-product. 12.9 grams of S-propenyldiethyldithiophosphate, boiling between 71- "5 C. at a pressure oi 0.2mm. The yellow viscous liquid iistillation residue grams. 48.5%) was thedesired ..I-bis-diethylthiopnospnorvlmercaptopropane.

l)ia/v.l-i.\-.- .ilcd. for C. il O P S (percent): C, 32.03: H. 6.35; P.15.011 51.20. Found (percent); C, 32.05; H. 6.28; P. 4.715. s

EXAMPLE 5 H. .53: P. 12.18: 5. 15.21. Found (percent): C, 42.48; e1.7.41:1. 1234152537.

EXAMPLE 6 slllled mixture or 44.3 grams (0.28 mole) of 90%.iimethvldithiophosphoric acid. containing 10% trimethyidiihiopnospnate.and 20.8 grams l0.52 mole) of methyl acetylene in a Pvrex pressure tubewas heated at C. 1 01 hours. After releasing the excess of methylacetylme. A colorless liquid product was obtained, which, according tosilver nitrate titration, contained only 9% unreacteddimethvldithiophosphoric acid. The latter was removed by washing thesolution of the crude reaction product in 300 ml. of ether with two 100ml. portions of v" 0 aqueous sodium nvdrogen carbonate solution. Theether solution was then dried and the solvent evaporated in vacuo toyield the neutral product. A nuclear magnetic .CSOllfll'lCB (NMR)spectrum of this product indicated that t was about pure. ionicdiadduct. i.e., 2.2-bis-dimethlthiophosphorvlmercaptopropane. Inaddition. there were we compounds present in approximately equalquantities, l.e.. the monoauduct and the trimethyldithiophosphate. Theywere carefully removed by distillation at a pressure of 0.000 mm. froman 85 C. heating bath. in this manner 32 grants i71%) of pure ionicdiadduct was obtained as a yellow distillation residue. This diadduct,when heat- :d to temperatures above C. under 0.8 mm. of pressure.thermally dissociated into the ionic monoadduct, 8-isopropenyiuimethyldithiophosphate and dimethyldiihiophospnoric acid. Thesecomponents, however. recomiined in the distillation receiver flask atroom temperatire.

IXAMPLE 7 The reaction described in the previous example was car- "ledout under the same conditions but in the presence of )5 gram 02 mole) ofbenzoyl peroxide. The decomposition of the peroxide under the reactionconditions was ndicated by the development of reddish brown color andthe precipitation of a crystalline solid. apparently benzoic icid.Titration. NMR analysis and workup of the reacl01'1 mixture indicatedthat the ionic diadduct described in the previous example wa formed asthe main product 31.5 grams. ;.e.. 70%

EXAMPLE 8 stirred mixture of 18.8 (0.1 mole) of distilled ditxihvldithiophoshoric acid and l2 (0.3 mole) of methyl acetylene in a Pyrexpressure tube was stirred at room *emperature for 14 hours. The reactionmixture was then sampled for analyses and then heated at 40 C. for 24hours. Analyses of the the intermediate and final reaction mixture afterthe release of excess methylacetylene were carried out by nuclearmagnetic resonance (NMR) spectroscopy. The neutral mixture of finalproducts after the removal of the unreacted acid by washing with aqueoussodium hydrogen carbonate solution in the usual manner was also analyzedby NMR. The results are tabulated below:

Triton X-100 emulsifier (an alkyl aryl polyether alcohol) to give sprayemulsions of 0.0250.050% concentration.

Phosphorus equivalents in the form 01- Ionic adducts, percent RadicalMonomonoadducts, percent Unreacted (C2H5O) PS2C=CHz Di- (C2H5O)2PS2CH=CHReaction mixture acid, percent after- (CzHsOhPSzH CH [(CzHsO)zPS2]C(OHa)2 CH;

24 hours at 25 C 90 8 Plus 24 hours at 40 C 48 15 35 2 Plus acidremoval. 28 71 1 The results show that the use of the threefold molarexcess of methylacetylene at 40 C. resulted in the formation ofsignificant amounts of the ionic monoadduct as well as of major amountsof the diadduct. After the removal of the acid, the crude product wasdistilled in vacuo. The ionic monoadduct was distilled as a colorless,mobile liquid between 44-46" C. at 0.1 mm. pressure from a bath of 100C. The ionic diadduct was obtained as a clear, yellow liquiddistillation residue. The structures of both adducts were determined byNMR.

EXAMPLE 9 A mixture of 9.3 g. (0.05 mole) of distilled diethyldithiophosphoric acid and 16.0 g. (0.40 mole) methyl acetylene wasreacted at 40 C. The reaction mixture was analyzed at periodic intervalsby NMR in the manner described in the prevoius example. The results aretabulated below:

Phosphorus equivalents in the form of Ionic adducts, RadicalUnreactpercent mono- Rcaetion mixture at 40 C. ed aci adduct,altcrpercent Mouo Dipercent The results show that the use of theeightfold molar excess of methylacetylene at 40 C. resulted in theformation of the ionic monoadduct as the major product.

EXAMPLE 10 dithiophosphate, 30 mole percent ofbis-2,2-dimethylphosphorylmercapto propane, and mole percent oftrimethyldithiophosphate, the latter as an impurity from the startingacid.

EXAMPLE 11 The products of Examples l-4 and 6 were each dissolved inacetone and dispersed in distilled water with Each of these emulsionswere used in standard laboratory insecticidal and miticidal tests asdescribed hereinafter. Portions of the results are tabulated in Table I.

Insecticidal tests Housefly tests.Fifty adults of the CSMA (ChemicalSpecialties Manufacturers Association) strain were sprayed in a 2" x 5"diameter stainess steel cage faced on top and bottom with 14 meshscreen. Flies were retained in the cage in which they are sprayed forknockdown observations and 24-hour mortality determinations. Mortalitywhich results from this test may be from residual contact as well as bydirect contact spray. DDT at 0.05% concentration was used as thepositive standard.

Mexican bean beetle tests.Lima bean leaves sprayed on the dorsal andventral surfaces were offered to ten larvae of the Mexican bean beetle(late second instar) for a 48-hour feeding period. The feeding rate andmortality data were recorded as well as foliage injury if any, wasrecorded. DDT at 0.05% concentration was used as the positive standard.

Systemic insecticidal activity was evaluated by applying 20 ml. spray ofthe sample to the vermiculite substratum of potted pea plants.Forty-eight hours after application, the plants were infested with 10adult pea aphids and mortality determination was made after 5 days.Demeton at 0.01% concentration was used as the positive standard.

Miticdal tsts Spider mite tests.Lima bean plants were infested with50-100 adults of the strawberry spider mite, T etranychus atlanticus,prior to testing. The infested plants were dipped into the test materialand held for five dyas. Adult mortality as well as ovicidal action wasnoted. Aramite and Ovotran were used as positive standards at 0.1%concentration.

The data of Table I shows that all of the compounds tabulated are activepesticides. The data further show that the somewhat more hydrophilicpropenyl dithiophosphate mono-adducts of Examples 1 and 2 have strongsystemic pesticidal action, i.e., they are transported throughout theplant via the plant sap. In contrast, the bis-dithiophosphate adducts ofExamples 3, 4 and 6 have only a contact action.

TABLE I Mortality, percent Mexican Pea. aphids Compound Spray beau Mitescone beetles, Contact, Systemic, contact Example Structure percent 48hrs. 48 hrs. 5 days 5 days 1 (C}I3())2PS CH=CH 0.050 100 50 100 01 1 0.025 100 50 100 50 S C Us 2 (C2Il50)2P-S CH=CH 0.050 100 100 100 62 0.025 100 10 50 S CH3 3 (CH30)2P--SCH2CHSP(COH3)2 0.050 100 100 0 100 I 0.025 100 30 0 50 CH S 4 (C2H5O)Q HS CH2CI{ S P(OCi'H5)z 0.050 0 0 82 SOH: S

6 (OHsO)QTH-SCISP(OCIH)2 0.050 50 0 100 II S mason EXAMPLE l2 S-propenyldimethyldithiophosphate. as prepared in Example l, was tested as anematocide at 0.41 gram per gallon of soil equivalent to 100 lbs. per4-inch acre. in the regular test, root knot nematodes (Meloidigyneincognita) were reared in a tomato plant-soil medium. 5oil for testpurposes was inoculated with infected soil and root knots from infectedtomato plants. The sample was in the regular extreme pressure test,(load-bearing capactty SAE" Federal Test Method 6501.02 (15.15.1955)],1W0 lubricated metallic surtaces were turned over each other at a rateor 1000 r.p.m. with 3.4/1 rubbing ratio unier increasing pressure untllseizure occurred.

The data at Table 11 show that the diisopropyldithiophosphoric acidmonoadduct of methyl acetylene ls supenor in this test to the zincdialkyldithiophosphate.

ABLE ll IKE lube stability test xltiation lll'l'OSlOl'l. Extrvlllo(500511.31. 'Hlllll )ltSSUl'O .tvublt. st-c. lrliltle. mg. l-llall 'vst.max. ltlttltlw (war lest pressure (llt' llllt-r Lear, lbs.) ttl o IK1011. lialut'ter. 51'12111'0 Adtlltlve components ltl'ctlli P .illtial:on til. .u/Pb a :lt-

1. Base 01] L8 1451 '(rl to 100 2. Zinc dialkylditltlo hospttate 1 tilit I is J: mi; 1. (sun 3. S-propenyl diisopropyldlthiophospltate l. 1 l5l, -43 l. :33 000 EXAMPLE 14 blended thoroughly with the soil in aV-shell blender. Four l-pint paper pots were used for each treatmentwith one tomato transplant per pot. After 3 to 4 weeks under artificiallight and overhead irrigation .the roots of the plants were examined fordegree of root knot formation. inoculated controls normally have aboutS100 root knots per plant. Percent control was determined by acomparison of the knot counts on treated and untreated tomato plants.When tested in this manner, S-propenyl dimethyldithiophosphate showed100% control.

EXAMPLE 13 The monoadduct of diisopropyldithiophosphoric acid and methylacetylene (S-propenyl diisopropyldithiophosphate) was prepared asdescribed in Example and tested for activity as a lubricating oiladditive. The product of this example was prepared with otherdialkyldithiophosphoric acid adducts including a zinc salt of a mixtureof isobutyl and n-amyl dithiophosphoric acids. in each instance, thecomopsition was prepared by mixing a small amount of the additive (0.1weight percent based on phosphorus) with a major portion of a minerallubricating oil. The mineral lubricating oil employed in the tests wasS.A.E. 30 grade 100 V.I. oil.

In the oxidation stability test. the oil was aerated at 207 C. (34031F.) for 23 hours in the presence or silver and copper-lead specimensattached to a shaft spun at a rate of 600 r.p.m. The extent of oxidationwas measured by the increase of viscosity of the oil. The corrosivity orthe oxidized oil appears as a weight change in the metallic specimens.After 3 and 19 hours, these specimens were replaced by new ones;consequently, the weight losses referred to the three intermediateperiods between the start of the experiment and 23 hours.

The data shown in Table 11 indicate that thc diisopropyldithiophosphoricacid monoadduct of methyl acetylene has antioxidant activity comparableto the activity of the zinc dialkyldithiophosphate.

The four-ball wear test (H. L. West, J. Inst. Petr. 32. 210, 222 (1946)was used for the characterization of hydrodynamic lubrication of steelsurfaces by the oil. in the test, 3 steel balls were placed in a fixedtriangular position and the fourth was mounted above them. The fourthball was mounted in a chuck so that the assembly could be rotated underpressure while lubricated with the oil to be tested. The tests werecarried out at a rotational speed of 1800 r.p.m. under kg. of pressureat 150 C. for minutes. Then, the balls were microscopically examined forscar diameters with are, of course. directly proportional to the wear.

The data of Table I1 show that the diisopropyldithiophosphoricacid-methyl acetylene monoadduct has better preventive wear propertiesthan the zinc dialkyldithiophosphate.

A. mixture or 44.6 grams (0.2 mole) of S-propenyldic-thyldithiophospnate and 18.6 grams (0.3 mole) ethanehiol waslrradiated in a quartz vessel with a IS-watt Hanau high pressureultraviolet lamp under nitrogen with stirring at 17 C. The progress ofthe addition reaction was followed by nuclear magnetic resonance (NMR)spectroscopy. in the absence of irradiation. no addition occurred. After1 hours of irradiation. 32% of the S- aropenyl diethvldithiophosphatereacted. NMR indicated this degree or disappearance 01 its unsaturation.in 24 hours. 77% JOHVCISlOl'l ot' the olefin was obtained. Subsequently,:he liquid reaction mixture was diluted with (50 ml. of ether and washedwith two 40 ml. portions of 5% aqueous sodium hydrogen carbonatesolution to remove any acldic by-product. The ether phase was then driedover anhydrous sodium sulfate and distilled. After :he removal of theether. the unreacted S-propenyl dizthyldithiophosphate was recovered.This was followed by the distillation of 33 grams (77% on the basis ofthe converted S-propenyl diethyidithiophosphate) of the 5-2-ethylmercaptopropyl diethyldithiophosphate as a colorless liquid yith ayellow .ll'li. boiling between -102 C. at 0.5 mm. pressure. An NMRspectrum of the product and 1115 elemental analysis confirmed itsstructure. Gas chromatography showed it to be a single compound, free ofstructural isomers and impurlties.

ina/ysm-Calcd. for C H O PS (percent): C, 37.48; H. 7.33; P. 10.73: 5.33.36. Found (percent): C, 37.45; H. 7.181P, 10.8715. 33.7.

EXAMPLE 15 iXAMPLE 16 12.6 grams (0.01 mole) of S-propenyl di- & mixtureor ethyldithiophosphate and 9.6 grams (0.2 mole) methanethiol wasreacted in a quartz pressure tube under autogerlous pressure for 14hours in a manner described in Ex- .tmpie 14. NMR indicated 8%conversion. Vacuum distlllatlon yielded 16.6 grams l77.5%) ofS-Z-methylmer- In the mice tests, adult male mice of the Swiss-Websterstrain were given single calculated doses via a stomach syringe andobserved for survival during a two week period. Doses ranging from 10 to1000 mg. per body kg. were used. Each dose level was administered to atleast two mice.

In the rats tests, each test compound was administered orally by stomachtube to five to eight groups of five male albino rats of theSprague-Dawley strain, weighing 220 t 0 300 grams. Following intubation,the animals were closely observed for mortality and toxic eifectsperiodically for a total time of 14 days.

In the cats test, young adult cats weighing between 2.6 and 3.8kilograms were closed via stomach tube with a calculated amount of thetest material. Two to four cats were used at each dose level. Dosagesranged from S to 300 mg. per body kg. The animals were then observed for48 hours for symptoms of toxicity.

The results of all the above tests are summarized in Table IV. Themedian lethal toxicities indicate the com- 1 6 EXAMPLE 22 EXAMPLE 23Toxicological tests of the compounds of Examples 15, 16 and 18 were alsocarried out using guinea pigs. In these tests, the test compounds wereadministered orally and subcutaneously to guinea pigs which wereobserved for toxic effects for at least 24 hours. A summary of the dataare given by Table VI. These data indicate the same order of toxicitywhich was found on mice, rats and cats.

On the basis of their reduced toxicity towards mammalians, our novelcompounds can be used for animal TABLE I\'.-AC UTE ORAL 'IOXICITIES OFSTRUCTURALLY RELATED TH IOPIIOSPHATE INSECTICIDES 1! Reported by G.Schrader in Die Entwieklung neuer insektizider Phosphorsaure- Ester,"Verlag Chemie, Weinheim, Germany, 1963.

b The corresponding monothiophosphate was used.

pletely unexpected detoxifying eifect of the B-methyl group of our newcompounds.

insect control where structurally related known compounds such asDisyston cannot be applied.

TABLE V Detailed toxicity data on structurally relatedbis-dithiophosphates (3H3 Dosage (CzH5O)zPS-CS-P(OCaHs): level of H i lltest com- S CHa 8 pound, nigJkg. Tertiary ester of Example 8 Secondaryester of Example 4 S CH3 S Primary ester (known) Number of dead rats outof two, on administration of test compounds l The test was repeated withanother two rats.

TABLE VI.-RESULTS OF ORAL AND SUBOUTANEOUS TOXICITY TESTS ON GUINEA PIGS(CHsOhPSgCHgCHSCHa (CHzOhPSzCHzfiJHSOzHs (CgH5O)2PSnCHgC)HSCH3 a CHaMethod of administration of test compound to guinea pigs Example 18Example 15 Example 16 Minimum lethal dosage to guinea pigs, mg. testcompound per kg. pig

Oral 100 100 10 Subcutaneous 100 100 25 13 captopropyldiethyldithiophosphate as a yellow liquid boiling between ll-l04 C. at apressure of 0.05 mm.

Analysis.Calcd. for C I-I O PS (percent): C. 35.02; H, 6.97; P, 11.29;S, 35.02. Found (percent): C. 35.11; H. 7.04; P, 11.42; S, 34.85.

EXAMPLE 17 (-958) To 37.2 g. (0.2 mole) of distilled diethyldithiophosphoric acid 17.6 g. (0.2 mole) of allyl methyl sulfide wasadded and the mixture was irradiated with stirring at 15 14 truth or theresulting reaction mixture showed that 89% at the propenyl ethyl sulfidereacted.

To remove the starting acid. the crude mixture was dissolved in 500 ml.ether. washed twice. with 100 ml. por- :tons of 5% aqueous sodiumhydrogen carbonate solution. The ether phase was then dried anddistilled in vacuo 0 remove the solvent and the unreacted propenylsulride (the last with a bath at 50 C. under 0.05 mm. pressure). In thismanner. 35.2 grams (74%) of the adduct were obtained as a residualliquid product. NMR inn for 3 hours- A subsequent NMR analysls 01 Plicated that the structure or the adduct was that of 21 indicated nodecrease of unsaturation. After the addition hioaceml resulting by ionicaddition, Le 1 0f mole) more acid, the mixture was fl mercaptopropyldiethyldithiophosphate. NMR also lndlated for another 24 hours. Thisresulted in a complete dls- Muted a mml'mum pumy f 95% f this productappearance of the unsaturat on- Analysts-Called. for C H O PS (percent):C. 37.47;

To remove the excess acid, the solution of the crude re- 33; p 73 5 33Found (percent); Q 3&1 1; action mixture in 300 ml. ether was washedwith two 100 PL p 7; 3357 ml. portions of 10% aqueous sodium hydrogencarbonate in attempt to f h if the above product by SolutiOIl- The etherPhase was then drlefl Over anhydrous distillation at a pressure of 0.02mm. resulted in a partial sodium Sulfate and distilled- After stripplngOfi the solvent decomposition to weld diethyldithiophosphoric acid. Thefractional di i in VaCUO yielded 38 (7.6%) of the listilled product.obtained between l06-l08 C.. was an adduct as a light yellow mobileliquid. Analysis of the adadduct f about purity according to NMR, ductby NMR showed that it was s2- l-met y 1 AMPLE m propyl dithiophosphate,i.e. the u-methyl substituted ester arising Markovnlkflv YP addition-The compounds of Examples 14-19 were tested as m- AnalYsiS-4a1cdfor B l92 2 (percent): C. 3502; tecticides. mlticides and nematocides in themanner de- Found (pe ce C. 3511; acribed in Examples 9 and 10. Inaddition, the approxi- H, 7.04; 11.42; S, 34.85. mate range ot themedian lethal oral dosage of the various EXAMPLE l8..-alkyimercaptopropyl dlalkyldlthlophosphates was de- J0 lermlned onmice. in this latter test. adult male mlce of A mtXture f 3 -3 gr mole)of s'pl'openyl j he Swiss-Webster strain. 30-35 grams in weight. weremethyldithiophosphate and grams. fnole) 0t given a single calculateddose via a stomach syringe and methanethiol was reacted under theconditions ot Example .mserved f Survlva] during a twwweek rjod The data1 After bleeding 0if the excess of melhanelhlol, a Crud}? of all thesetests are shown in Table 111. They indicate Pmdllct containing 90% ofscz'methylmercaptopl'opyl that the S-Z-alkylmercaptopropyldialkyldithiophosphate methyldithiophosphate WaS obtained. was washed 85type compounds of [he present invention are desual t0 m ve the Unreactedacidsubselilllent fl'acllonal sirable. relatively safe to use pesticideswhile the isomeric distillation in Vacuo yielded 34 grams (70%) Purified:ompounds !Examples 17 and 19) are practically worthy p p pydimethyldithiophosphate 88 21 less in this respect. Surprisingly. themethyl branching in less liquid, boiling between 98-l00 C. at 0.05 mm.presthe l-position favorably affects the biological activity of sure. hecompounds or this invention. in contrast methyl or Arzalysis.Calcd. forC H O P (p rcent): C. 29.25; ethyl branching in the 1-position has anadverse effect H, 6.13; P, 12.57; S, 39.05. Found (percent): C. 29.58:on he pesticidal activity of compounds having similar H, 6.37; P, 12.73;S, 39.22. II'UCl11IS.

."ABLE Ill *ercent mortality produced by percent spray) Percent Median.louse Mexican been beetles ea .tDlllllS llites outine lethal dose llies24 eontrul of loral on lrs. ontact. System10. imitact. systemic..olltact. Systemic. nematodes mice) Example 0.01) 8111's. .1 days 25hrs. lays 8 hrs. 1 days at 40 lbs. L850 Number Structure of compound 1).01) O. 01) 0.001) 0. 001) 0.001) 10. 001) per acre rug kg.

18 (CHaOnlSCHzCHSCIh 1:0 )0 )0 .12 100 .00 30-100 15(CH3O)21PSCII2CIISC2II5 l 0 ill) l in :0 00 u) 100-300 16 (C2HO)21ISCH1CHS(H3 l 00 )0 i) s 00 .5550

s cm

17 (CzIIgOhlTSCHCHzSCHa l l l 35 I S CH:

14 (CzHtOhlTSCHQCHSCtHt .1) 0 l l 1 )0 225-50 s but 19 (CZH5O)ZPSCHSC2H5l .i l

EXAMPLE 19 EXAMPLE 21 20.4 grams (0.02 mole) of propenyl ethyl sulfidewere added slowly with stirring and water cooling between 20 40 C. to27.2 grams (0.2 mole) of diethyldithiophosphoric acid. An exothermicreaction took place. The intensity of the olefinic hydrogen signals inan NMR spec- The acute oral toxicities of the compounds of the presentinvention were investigated in comparison with struc- .ural1y relatedknown thiophosphate insecticides. Approximate median lethal toxicitieswere determined on mice, rats and cats.

17 EXAMPLE 24 The relatively nontoxic compounds of Examples 18 and 15were tested as animal insecticides on guinea pigs infested withengorging nymphs of the lone star tick [Amblyomma americanum (L.)] andlarvae of the secondary screw-worm [Cochliomyia macellaria (Fabricus)]and of the black-blowfiy [Phormia regina (Meigen)]. Stable flies[Stomoxys calcitrans (L.)] are fed on the guinea pigs at 4 hours aftertreatment. Engorged fiies are held for 24 hours to see if they arekilled by the blood they ingested.

The test compounds formulated as 5% solutions in Tween 20, were orallyadministered at an initial dosage of lOO mg. per kg. If any of thearthropods were killed, the dosage was lowered to the minimumsystemically effective dosage. The results are shown by Table VII. Thedata indicate that both of the compounds are effective in controllingall the insect species at a dosage of 100 mg. per kg.

EXAMPLE 25 The compounds of Examples 16 and 18 were also tested oncattle as animal insecticides. The tests of this example were designedto determine if these insecticides are systemically effective againstcommon cattle grubs, [Hypoderma lineatum (de-Villers)]. Cattle weretreated in Texas, when cattle grubs were located in the internal tissuesof cattle, after the end of the heel fiy season and before grubs appearin the animals backs, i.e. in June. Cattle grubs began to appear inthese animals backs in September. Peak numbers were found in December.To determine the effectiveness of the treatments, animals were examinedmonthly and as cattle grubs appeared in these animals backs, they wererecorded to obtain cumulative counts of the total number of grubsencysting in the back of each animal. The results of the oraladministration of the test compounds are shown by Table VIII. The dataindicate that the compounds, especially the compound of Example 18provides a high degree of systemic control.

18 EXAMPLE 2c The compounds of Examples 14 to 16 and 18 were also testedas cattle insecticides for the prevention of reproduction in Boophilusticks. Colonies of the cattle tick [Boophilus annulatus (Say)] and theSouthern cattle tick [Boophilus annulatus microplus (Canestrini)] weremaintained.

Larvae from the colonies were placed onto cattle and in 3-4 weeksengorged female ticks drop off the cattle onto the floors of stalls andare collected for use in the screening test.

In the laboratory, these ticks were washed, dried, and sorted intogroups of 10. Each group is weighed and only those weighing more than 2g. are used.

The test compounds were formulated as emulsifiable concentratescontaining 25% active ingredient, xylene, and 10% Triton X-100emulsifier. They were then routinely tested at concentrations of 1%,0.1% and 0.01%. The 1% concentrations are prepared immediately beforeticks are dipped and lesser concentrations are obtained by serialdilution of the 1% concentration.

Ticks were dropped into 50 ml. of the insecticide. The liquid with theticks is stirred vigorously for 30 seconds and then poured through ascreen that retains the ticks. After a short time on the screen theticks were transferred to paper toweling and allowed to dry. Ticks werethen placed in 8 dram shell vials with paper covers and held in aconstant temperature cabinet at -l F. and 70-80% relative humidity.

After 2 weeks the ticks were examined, and eggs were weighed. The tickswere discarded at this time but the eggs were held for another month. Atthe end of this period the percent hatch was estimated.

For use as controls, a number of ticks are dipped in an emulsion of 2.6%xylene and 0.4% Triton X-100.

Test solution was considered elfective for prevention of reproduction inBoophilus ticks if weight of eggs laid by treated ticks is less than 10%of weight of eggs laid by control ticks and/or 10% less of the eggshatch.

The minimum effective concentrations of the test compounds are given inTable IX. The data show that at 1% concentration all our compounds wereeffective. The more effective compounds, i.e. those of Examples 14 and16, provided control of reproduction at 0.1% concentration.

TABLE VIL-RESULTS OF TESTS ON GUINEA PIGS FOR ANIMAL SYS TEMICINSECTICIDAL ACTIVITY Lowest oral dosage causing kill 01- TABLEVHL-RESULTS 0F TESTS ON FOR SYSTEMIC CONTROL OF CATTLE Number of cattle-Average Dosage 01 number Percent treatment Example Number Chemicalstructure In test Infested of grubs control (mg/kg.)

18 (CH OhfiSCHzCfHSCH: 3 2 4.7 74 5 8 CHI:

16 (CgH OhfiSCH fllHSCH; 3 1 1.0 94 10 S OH ' n 11 13.3 0 None LowestIIecLivrconcentration 1i 0st compound, percent,

"outhcrn 5 13 22 621 1 Chemical structure The @321: i c ii 18(CHaOhPSaCHgCHSCH;

15 (CHBOMPSzCHzCHSCzIh l6 (CaHaOhPSzCHnCy'HS C113 Li 1 14(CzlhOhISzCHzCHS(1H5 v.1 i 1 What is claimed is: 1. A compound havingthe formula fi-SCH -CH-SR: R10 5 cu,

2.0 wherein R and R are C to C aikyl radicals and R is C to C aikyl.pnenyl, C to C alkylphenyl, C to E phcnylalkyl cnlorophenyl,bromophenyl, nitrophenyl. Z. A compound according to claim 1 wherein R Rand R are methyl. ethyl or propyl. 3. A compound of the formula ulian$Cllz-CiI-S-Ciiillzw 'wiiz qo S Illa wherein m and n are l or 2 l. Acompound according to claim 3 where m is 2 and .EWIS GOTTS. PrimarvExaminer i. H. SLTTC). ASSISIaI'lI Examiner

